Many hydrophobic and lipophilic environmental toxicants when consumed through diet are absorbed by passive diffusion across the gastrointestinal tract. The extent of absorption of these chemicals during gut passage and the factors governing their absorption are critical in determining the absorption efficiency of chemicals ingested through diet. In this research we will test the hypothesis that lipid load in the diet modulates fluoranthene (FLA; a toxic, and mutagenic polycyclic aromatic hydrocarbon compound) absorption resulting in conversion of FLA to its reactive metabolites in the body and in the extent of DNA-adduct formation. We propose the following three specific aims to test the hypothesis i) to study the bioavailability, metabolism and toxicokinetics of orally administered FLA and the fate of reactive metabolites in different concentrations of dietary fat and at different doses, ii) to estimate the disposition of FLA using a physiologically based pharmacokinetic model, and iii) to investigate the influence of dietary fat on formation and persistence of FLA-DNA adducts in target tissues. Our expectation is that findings from this research will provide us with a comprehensive picture of the fate and consequences of carcinogenic chemicals ingested through lipid rich diet. Results from these studies are significant in that they contribute to a greater understanding of the role played by dietary modulation on disposition of FLA in the body and the mechanisms by which bioavailable dose contributes to carcinogenicity.